Conversion of hydrocarbons



alumina, clay, etc.

Patented Jan. 14,

UNITED srATEs PATENT orr cs CONVERSION or mnocAitBoNs Edwin 'r. LayneJersey City, N. 1., assignor to The Polymerization Process Corporation,Jersey City, N. J a corporation of Delaware No Drawing.

Application December 30, 1942, Serial N0. 470,687

Claims. (01460 -671 This invention relates .to improvements in catalyticconversion processes which involve'the Such proc-' activation of olefinhydrocarbons. esses include the polymerization of olefin hydrocarbonsand the alkylation oi iso-paraflln and cyclic hydrocarbons by means ofolefin hydrocarbons.

The invention relates particularly to improvements in processes whichinvolve the activation or olefin hydrocarbons by means ,of catalystscomprising certain metal pyrophosphates as the essential activeingredients. Certain metal prophosphates, particularly those of copperand mercury but including also the pyrophosphates of zinc, magnesium,iron, aluminum and cobalt, are capable of promoting the polymerizationof olefin hydrocarbons and alkylation reactions involving olefinhydrocarbons such as the alkylation of arcmatic hydrocarbons by means ofolefinhydrocarbons.

Such pyrophosphates may be employed in the form oigranules consistingessentially only of the pyrophosphate but preferably they are employedin the form of granules or pellets which comprise one or more of thepyrophosphates in combination with suitable supporting material. Incombining the active pyrophosphates with supporting material in thismanner it is necessary. to avoid the use of certain natural materialswhich have been employed generally as catalyst supports; These includeIn general the use of metals or oxides of metals, particularly those ofthe alkali and alkaline earth series should be avoided This care in theselection of supporting materials is made necessary by the manner inwhich the above-mentioned pyrophosphates become active. Each of thepyrophosphates mentioned above becomes active for the promotion'of thehydrocarbon conversion reactions by the formation there-,

in, under the conversion conditions, of an active modification which isprobably the true catalyst Ior the reaction. Consequently in theselecsilica, 1 kieselguhr tin and lead. Other materials include'suitablesalts suchas thesulphates of barium and calcium.

However, it is found that carbonaceous materialsarel particularlysuitable as supporting materialsbecause of their stability under theconditions of operation and relative porosity and the ease'with whichthey, maybe obtainedas, .or formed into, granules of the desired sizeand porosity. Suitable materials include various charcoals and cokes aswell as materials which "may be converted by relatively mild heating tothe desired non-volatile form such as petroleum' residues and asphalts.However, carbonaceous 1940, which issued on February. 2, 1943, as Patentrender it more economical to replace the used .catalyst at the end ofeach operating run with No. 2,310,161. Catalytic material thus preparedis capable of activating olefin hydrocarbons in cata- I lytic conversionprocesses involving long .operating runsresulting in a yield of productper unit quantity of catalyst which is sufiiciently large to freshcatalyst than to regenerate r reactivate a the used catalyst. Atthe endof each operating tion of. a supporting material it is necessary toavoid the use of those, materials which would ,react with ,the activemodification of the pyrophosphate and thus depress the activity of thecatalyst mass as a whole. Materials which have been foundsuitable foruse as supporting materials for the pyrophosphates include the normaland acid' salts oi thevarious phosphoric acids which are notsubstantially reducible under the conversion conditions, such as thephosphates of calcium, strontium, barium; titanium, zirconium, cerium,thorium, silicon and germanium,

run, thereiore, the used catalyst is removed from the reactor andreplaced with fresh material.

At the end of such long operating runs it is found frequently that thegranular catalyst mass has set into arigid structure which is difficultf to reinove from the. catalyst chamber. Alternatively, the catalyst issometimes: found as a plastic or sticky mass, the exact condition beingafunction of a history of the use of the material. These conditionsresult apparently in part from changes in the chemical and physicalstate of the catalyst which form liquids which cause the catalystgranules to adhere. If the granules are in the term of compressedpellets the liquids may cause swelling which promotes adherence.Adherence of the granules to each other is promoted also bythe cementingaction of highly polymerized materials "which accumuto relatively highboiling products. tion of these various liquids by the non-catalyticgara es late on the surfaces of the catalyst granules during the oerating run. The setting of the granular mass in this manner presents aparticularly diflicult task of removing it from' reactors in which thecatalyst mass is contained in elongated tubular chambers.

The effects which promote setting of the catalyst mas s also tend tolimit the length of the operating run. The formation of liquids by thechanges in the chemical state of the catalyst softens molded catalystpellets. This may cause swelling and deformation of the catalyst pelletswith the result that the mass becomes unduly consolidated and presentstoo great resistance to the flow of the reactants therethrough.Softening of molded pellets is promoted also bythe accumulation ofpolymerized hydrocarbons, which also reduce the activity of catalystgranules of whatever nature by blanketing the active centers.

In this important application of the invention the difllcultiesattendant upon the removal of the used catalyst from the reactor areeliminated, and a greater yield of useful product per unit of catalystis achieved, by employing as the consolidated granular mass in thereactor a mechanical mixture of the granular catalyst and granularmaterial which is substantially inactive catalytically. The volumetricratio'of the granular catalytic material to the granular substantiallynoncatalytic material may vary from 1:1 to :1 but the preferred ratiosare from 2:1 to 3:1. The non-catalytic granular material conveniently isapproximately of the same granular dimension as the granular catalyticmaterial to facilitate the intimate mixing thereof with the catalyticmaterial.

Apparently the granular non-catalytic spacer the mass are minimizedandby preventing channeling of the'reactants in the catalyst mass. The

. spacer material also assists the reaction by acting as an absorbentfor liquids which are formed in the reaction zone. During the reactionthe pyrophfisphate catalytic, material undergoes chemical change withthe formation of .liquids which may be catalytically. active. Inaddition liquids are formed in the'reaction zone as the result ofpolymerization of the olefin reactants The absorp-- spacer assists inretarding adherence of the catalyst granules and setting of the catalystmass and furthermore minimizes b anketing of active cen-' ters ofthecatalytic material by the high boiling polymers. The retention ofthese tarry polymers by the granular spacer material reduces the amountof such polymers in the liquid product andjmprovs the color ofthelatter.

The materials which are useful as the noncatalytic spacer materialsincludein general the same materials which are chemicallysuitable foruse as supporting material for the pyropho' phates as described above.terial must occur naturally as, or be preformed into, granules ofsubstantiallythe dimensions of the granular or pelleted catalyticmaterial.

the phosphates and other salts mentioned above as supporting materials.It is preferred to employ granular' charcoal or other suitable granularcarbonaceous material. Granular charcoal is particularly suitable alsobecause of its relatively However, such ma- This requires thegranulation of materials such as a. high capacity for the absorption andretention of liquids and good mechanical strength. For example in thepolymerization of olefin hydrocarbons, such as a refinery mixtureincluding C3 and C4 oleiin hydrocarbons, it is found that the employmentof a mixture of three parts by volume of granular catalytic materialcomprising copper pyrophosphate in intimate mixture with finely dividedcharcoal and one part by volume of granular charcoal results in theattainment of a greater yield of useful product per unit of cat alyticmaterial employed as compared to the results obtained by the use of thegranular catalytic material alone and at the end of the operating run,which is reached when the degree of conversion reaches a-pre-determinedminimum, the

. catalyst mass is removed from the reactor in a relatively short time"without difilculty. While i ular catalytic material in a reactor whilecharging hydrocarbons to the reactor at the same rate results in asubstantial increase in the actual space velocity of the operationbecause of the decreased volume of the space in the reactor actuallyoccupied by catalytic material. In order to maintain the degree ofconversion at the same rate it may be desirable in some instances toincrease the reaction temperature slightly if this does notsubstantially alter the character of the liquid product obtained.

The substitution of the improved catalyst mass,

. comprising a mixture. of the catalyst granules with a substantialproportion of granules of the non-catalytic spacer material, for acatalyst mass of the same volume consisting entirely of the alyticmaterial.

granular catalytic material, and the passage of the reactants throughthe catalyst 'mass at the same rate as before such substitution, mayresult in a slightly more rapid deactivation of the catalyst because ofthe increase in space velocity, expressed" in terms of volume ofreactants per unit volume of actual catalyst space. Under suchcircumstances the conversion rate may decline to the predeterminedminimum in a shorter time whereby the operating run must be terminatedin a shorter time. in practise that the substitution of themixedgranular mass as described above results generally in a longer operatingrun, presumably hecause of the effect of the porous spacer material inabsorbing and retaining liquids which might otherwise blanket the activesurfaces of the cat- In all cases, however, whether the operating run islengthened or shortened by the new method the yield of useful productper unit of catalyst employed is increased because of the effect of theporous spacer in maintaining the. activity of the catalyst,

Preferably sufiicient reactor space is provided to accommodate thespacer material while leaving a remaining catalyst space sufficientlylarge to permit charging thereactants at the desired rate whilemaintaining the desired space velocity;

' In any case the yield of usefulfproduct per unit However, it has beenfoundthe time required for cleaning the reactor in each change-over.

A further advantage of the use of the spacer material results from itseffect in minimizing over-heating of the catalystas the result of theexothermic heat of reaction. As the reactants pass through the reactionzone they pass through a zone of maximum temperaturewhich results fromcontact of a relatively high concentration of olefin reactants with abody of relatively fresh catallytic material. As the catalytic materialwhich is contacted by the highest concentration of reactants becomesdeactivated the concentration of reactants in contact with a succeedingmass of catalysts is increased due to the lowered degree of conversionwhich occurs during the flow of the reactants over the deactivatedcatalyst. Consequently, there is, throughout the operating run, a zoneof maximum conversion and maximum temperature which proceeds from thepoint adjacent the entrance of the reactor to a point adjacent the exitthereof. Such concentrations of the heat generated by the exothermicreaction lyst mass.

. 6 tained upon a 4-mesh' screen. When using "this combination ofgranular material a ratio of three volumes of the catalyst granules toone part of the charcoal has been found tobe satisfactory.

The reaction conditions employed when using a catalyst mass containingsubstantially noncatalytic spacer material in accordance with thisinvention are substantially like the reaction conditions which areemployed when using a similar catalytic material without the inclusionof the non-catalytic granular material in the cata- However, certainadjustments in the temperature and space velocity may be required tocompensate for the difference between the volume of the catalyst massand the space actually occupied by the catalytic material. In thepolymerization of olefin hydrocarbons any suitable pressure may be usedbut it is preferred to employ relatively high pressure, for example in.ex-

are deleterious since they promote production of tarry material,degradation of the catalyst granules and the setting of the consolidatedmass into a rigid structure. The inclusion of the granular non-catalyticmaterial in the catalyst mass in accordance with this inventionminimizes the maximum temperature reached in the reaction mass byenlarging the zone in which reaction occurs principally and by providingheat adsorptive material at thezone of maximum temperature which adsorbsheat and assists in itstransfer from the zone of maximum temperature. Inthis manner overheating of the catalyst is minimized and the useful lifeof the catalyst is lengthened.

As mentioned above carbonaceous materials are preferred as thenon-catalytic granular material since they may be obtained in thedesired granular form without the necessity of pelleting or extrusion.While coke from the carbonization of coal or petroleum maybe employed itis less desirable than charcoal since the coke may contain substantialquantities of sulphur which may contaminate the hydrocarbon product.Coke'produced by the carbonization of coal may have the furtherdisadvantage that it contains residual or ash-like materials which arereactive with the pyrophosphate and its reduction products in the mannerdescribed above. Granular charcoal is,

1 therefore, preferred although the use of other suitable granular orpelleted carbonaceous materials is not excluded.

ciently coarse to preserve in the catalyst mass the cess of 150 poundsper square inch. although atmospheric pressure or lower pressures may beemployed. The reaction temperature depends somewhat upon the nature ofthe material under treatment of the product desired. In-the conversionof gaseous oleflns, such as butylenes and propylene,'temperatures of 300to 500 F. may be employed. In the conversion of hydrocarbon gases thehydrocarbon should be passed over the contact material at a rate of 2 tocu. ft. (measured as gas at standard conditions of temperature andpressure) per pound of catalytic material per hour. Otherwise expressedthe hydrocarbon reactants should be passed through the reactor at a rateof 50 to 6000 volumes per hour per volume of the catalyst mass. However,the space velocity is governed also by the degree of conversion desired.In a treatment of gaseous mixture containing isobutylene it may bedesirable to operate at a relatively high space velocity to limit theextent of conversion to the co-polymerization of iso-butylene or theinter-polymerization of iso-butylene and normal butylenes.

The activation of olefim'c hydrocarbons in other condensation reactionsis carried out suita bly at somewhat the same conditions as are employedin the polymerization reaction. In the propylation of aromatichydrocarbons the above desired permeability, but the use of granularsizes larger than necessary is undesirable since the advantages of theinclusion of this material in. the catalyst mass are realized to thefullest degree when the spacer isdistributed most uniformly throughoutthe catalyst mass. Conveniently the spacer material may be ofapproximately the granular size of the catalyst granules or pelletsalthough this is not essential. For example, when employing catalyticmaterial comprising an intimate mixture of copper pyrophosphate andfinely divided charcoal which has been extruded as %.inch cylinders andbroken into'about inch length; granular charcoal having an averagediameter of approximately A inch to /2 inch has been found to besatisfactory as to size. Material of this size is obtained in screeningoperations by selecting the material which passes through a 2-meshvibrating screen, but is reranges of'conditions of temperature, pressureand space velocity are satisfactory. For example in the propylation ofbenzene the mixture of benzene, propylene and accompanying inerthydrocarbons may be passed over the catalyst mass under a pressure of900 pounds per square inch at a temperature of 400 to 450 F. and at arate of 11 cu. ft. per hour per pound of catalytic material (exclusiveof spacer). In alkylation treat-,' ments' it 'is desirable also that thehydrocarbon to be aikylated by the olefin be present in the reactionzone in substantial excess in order to minimize co-polymerization of theolefin reactants. In the alkylation of aromatic hydrocanbons by means ofolefin hydrocarbons the mol ratio of aromatic to olefin hydrocarbonsshould be in excess of 1:1 and preferably should be 5:1 or higher.

Another application of the lnventiori"'involves the employment of spacermaterials in co'nnection with the activation of olefin hydrocarbons r bymeans of solid catalysts comprising phosphoricacid as the essentialactive ingredient. Such catalysts are preparedby impregnating suitablesupporting material such as carbonaceous gran- .ules with phosphoricacid which may bein either the ortho or pyro form or by the compoundingof the phosphoric acid with siliceousmaterials.

such as lrieselguhr and clays which are reactive with a portion of thephosphoric acid. Such reaction rovides a substantially porous mass ofthe reaction product of the binder and phosphoric acid which acts as asupport for the remainder of the phosphoric acid, the latterconstituting the essential active ingredient of the catalyst. The mannerin which such-solid phosphoric acid catalysts are combinedwith thespacer material and employed for activating-olefin hydrocarbons issubstantially the same as that described above in connection withthepyrophosphate catalyst. In connection with such solid phosphoric acidcatalysts the 'spacer material functions to strengthen the catalyst massas a whole, to absorb liquids, such as phosphoric acid and heavypolymers, to permit great yield of useful product per unit of catalystemployed and to permit easy removal of the catalyst mass from thereactor at the end of the operating run.

The granular spacermaterial used with solid catalysts comprisingphosphoric acid as the essential activeingredient are substantiallythose which'are satisfactory for use with the pyrophosphate catalyst; Ingeneral carbonaceous materials are to be preferred because they areavailable in a granular porous form and are substantiallynon-reactive'with the phosphoric acid. However, other suitable materialswhich are nonreactive with the phosphoric acid may be em--: ployed.

The granular spacer material and granular catalyst may be mixedsufficiently by charging them to the reaction zone simultaneously orthese materials may be mixed outside the reactor before charging thereactor. and catalyst granules may be arranged in the reactor asalternate relatively thin layers extending transversely to the path offlow of the reactants. This arrangement can be secured by chargingalternate quantities of spacers and catalyst to the reactor. With any ofthe above operations it may be desirable to provide larger bodies of thegranular spacer material at one or more places in the reactor. Forexample, a substantial layer of granular spacer material may be placedat the bottom of the reaction zone or in the bottoms of a pluralityofelongated tubular reaction zones.

I claim:

l. The method for activating olefin hydrocarbons in condensationreactions which comprises passing the hydrocarbons which enter into thecondensation reactions, under suitable, reaction conditions oftemperature, pressure and space velocity, through a consolidatedgranular mass essentially consisting of an intimate mixture of catalystgranules and spacer granules, said cat- 'alyst granules being inphysical non-adhering contact with saidspacer granules, each of saidcatalyst granules comprising an intimate mixture of a metalpyrophosphate capable of reduction to a catalyst for said condensationreactions and finely divided supporting material therefor, and each ofsaid spacer "granules being composed of material which is non-reactivewith the reduction products of said pyrophosphate.

2. The method for activating olefin hydrocarbons in condensationreactions which comprises passing the hydrocarbons which enter into thecondensation reactions, under suitable reaction conditions oftemperature, pressure and space velocity, through a consolidatedgranular mass essentially consisting of an intimate mixture of catalystgranules and spacer granules, said cat- Alternatively the spacerasraaoealyst granules being in physical, non-adhering contact with said spacergranules, each of said catalyst granules comprisin an intimate mixtureof copper pyrophosphate and finely-divided supporting material therefor,and each of said spacer granules being composed of material which isnon-reactive with the reduction products of said copper pyrophosphate.

3. The method for activating olefin hydrocarbons in condensationreactions which comprises passing the hydrocarbons which enter into thecondensation reactions, under suitable reaction conditions oftemperature, pressure and space velocity, through a consolidatedgranular mass essentially consisting of an intimate mixture of catalystgranules and spacer granules, said catalyst granules being in physicalnon-adhering contact with said spacer granules, each of said catalystgranules comprising an intimate mixture of a metal pyrophosphate capableof reduction to a catalyst for said condensation reactions and a finelydivided supporting material therefor, and each of said spacer granulesbeing composed of carbonaceous material.

4. The'method of activating olefin hydrocarbons in condensationreactions which comprises passing the hydrocarbons which enter into thecondensation reactions, under suitable reaction conditionsoftemperature, pressure and space velocity, through a, consolidatedgranular mass essentially consisting of an intimate mixture of catalystgranules and spacer granules, said catalyst granules being in physicalnon-adhering contact with saidspacer granules, each of said catalystgranules comprising an intimate mixture of a metal pyrophosphate capableof reduction to a catalyst for said condensation reactions and a finelydivided supporting material therefor, and each of said spacer granulesbeing composed of charcoal.

5. The method for activating olefin hydrocarbons in condensationreactions which comprises passing the hydrocarbons which enter into thecondensation reactions, under suitable reaction conditions oftemperature, pressure and pace velocity through a consolidated granularmass essentially consisting of an intimate mixture of catalyst granulesand spacer granules, said catalyst granules being in physicalnon-adhering contact with said spacer granules, each of said catalystgranules comprising an intimate mixture of a metal pyrophosphate capableof reduction to a catalyst for said condensation reactions and finelydivided carbonaceous supporting material,

and each of said spacer granules being composed of material which isnon-reactive with the reduction products of said metal pyrophosphate.

6. The method for activating olefin hydrocarbons in condensationreactions which comprises a metal pyrophosphate capable of reduction toa catalyst for said condensation reaction and finely dividedcarbonaceous supporting material, and each of said spacer granules beingcomposed of carbonaceous material.

7. The method for activating olefin hydrocarbons in condensationreactions which comprises passing the hydrocarbons which enter intothecondensatlon reactions, under suitable reaction conditions oftemperature, pressure and space velocity, through a consolidatedgranular mass essentially consisting of an intimate mixture of catalystgranules and spacer granules, said catalyst "contact with said spacergranules, substantially all granules of said mass having an-average divameter within the range of 4 inch to V inch,

granules beingin physical non-adhering contact with said spacergranules, each of said catalyst granules comprising an intimate mixtureoi copper pyrophosphate and finely divided carbonaceous supportingmaterial, and each of saideach of said catalyst granules comprising anintimate mixture of a metal pyrophosphate-capable of reduction .to acatalyst for said condensation reactions and fin'ely divided supportingmaterial.

therefor, and each of said spacer granules being composed of materialwhich is non-reactive witli the reduction'products of said metalpyrophosphatei 12; Thelrnethocl for polymerizing olefin 'hydro---carbons which comprises passing said olefin hydrocarbons at elevatedtemperature through a consolidated granular mass essentially consistingof an intimate mixture of catalyst granules and spa'cer granules, saidspacer granules being in physical non-adhering contact with saidcatalyst granules, said catalyst granules comprising an intimate mixtureof a metal pyrophosphate capable of reduction to a catalyst for saidpolymerising reaction and finely divided supporting material therefor,and said spacer granules being composed of material which isnon-reactive with coal, and each of said spacer granules being composedof charcoal.

9. The method for activating olefin hydrocarbons in condensationreactions which comprises passing the hydrocarbons which enter into thecondensation reactlons, under suitable reaction conditions oftemperature, pressure and space velocity, through a consolidatedgranular mass essentially consisting of an intimate mixture of catalystgranules, each comprising an intimate mixture of copper pyrophosphateand finely divided charcoal, and spacer granules of charcoal,

in proportions 01' 1 to 5 parts by volume of the catalyst granules toeach part by volume of the spacer granules.

10. The method for activating olefin hydrocarbons in condensationreactions which comprises passing the hydrocarbons which enter into thecondensation reactions, under suitable reaction conditions oftemperature pressure and space velocity, through a consolidated granularmass 7 essentially consisting of an intimate mixture of catalystgranules and spacer granules, said catalyst granules being in physicalnon-adhering contact with said spacer granules, the average diameter ofthe catalyst granules being substantially of the same order of magnitudeas that of the spacer granules, each of said catalyst granulescomprising an intimate mixture of a metal pyrophosphate capable ofreduction to a catalyst for said condensation reactions and finelydivided supporting material therefor, and each of said spacer granulesbeing composed of material which is non-reactive with the reductionproducts of said metal pyrophosphate.

11. The method for activating olefin hydrocarbons in condensationreactions which comprises the reduction products of said metalpyrophosphate. s

13. The method for alkylating aromatic hydrocarbons which comprisespassing said aromatic hydrocarbons and olefin hydrocarbons at elevatedtemperature through a consolidated granular mass essentially consistingof an intimate mixture of catalyst granules and spacer granules, saidspacer granules being in'physical non-adhering contact with saidcatalyst graning of an intimate mixture of catalyst granules passing thehydrocarbons which enter into thecondensatlon reactions, under suitablereaction conditions of temperature, pressure and space velocity, througha consolidated granular mass essentially consisting of an intimatemixture of catalyst granules and spacer granules, said catalyst granulesbeing in physical non-adhering ules, said catalyst granules comprisingan intimate mixture of a metal pyrophosphate capable of reduction to acatalyst for said alkylating reaction and finely divided supportingmaterial therefor, and said spacer granules being com-' posed ofmaterial which is non-reactive with the reduction products of said metalpyrophosphate.

14. The method for alkylating benzene with propylene which comprisespassing said benzene and propylene at elevated temperature'through aconsolidated granular mass essentially consisting of an intimate mixtureof catalyst granules and spacer granules, said spacer granules being inphysical non-adhering contact with said' catalyst'granules, saiddatalyst granules comprising an intimate mixture of a metalpyrophosphate capable of reduction to a catalyst for said alkylatingreaction and finely divided supporting material therefor, and saidspacer granules being composed of material which is non-reactive withthe reduction products of said metal pyrophosphate.

15. The method for alkylating benzene with propylene which comprisespassing said benzene and propylene at elevated temperature through aconsolidated granular mass essentially consistand spacer granules, saidspacer granules being 7 in physical non-adhering contact with saidcatalyst granules, said catalyst granules comprising an intimate mixtureof copper pyrophosphate and finely divided charcoal, and each of saidspacer granules being composed of charcoal.

EDWIN T. LAZY G.

